Which theologian set out to reform the church from within while avoiding direct opposition to the papacy?

Desiderius Erasmus is recognized for his attempts to reform the church from within, advocating for a return to the foundational teachings of Christianity and emphasizing the importance of personal piety and moral integrity. He sought to address the corruption and practices within the Church, particularly through his writings like "In Praise of Folly" and his critical examination of the Church's doctrines.

Erasmus believed in education and the study of classical texts as a means of reform, promoting the idea of a more contemporary and moral Christianity without directly challenging the authority of the papacy. His approach was characterized by a call for change through intellectual discourse and ethical behavior, rather than through confrontation or schism, which distinguishes him from other Reformers who took more radical stances against the Church.

This desire to reform the Church while maintaining a connection to the established order underlines why Erasmus is seen as the right answer to the question regarding a theologian who sought reform from within rather than through direct opposition to church leadership.